I have a GL with Speedbooster enabled (Tomato 1.07). No problem at all. I don't see what problems can be in your case, too. Of course you have to have speedbooster clients to have a high speed connection.

Speedbooster really doesn't have much effect - you should spend your money on better antennae (or Cat5 cable!) IMHO. My non-speedbooster built in intel wireless chipset laptop has much better range and throughput than a linksys WPC54GS. There are some detail reviews of Speedbooster (Broadcom Afterburner) on TomsNetworking. That concludes it does work - but only if you are very close the benefit drops off quickly with distance

So true mstombs. Also, the WPC54GS especially has really crappy range. With my WUSB54GS, which is a "Speedbooster adapter", I get better speed to my Tomato box if Afterburner is off on Tomato, with 4 bars signal in Win.